Optimisation and sensitivity analysis of friction stir spot-welding process parameters for joining AA 6061 aluminum alloy

2012 ◽  
Vol 7 (3) ◽  
pp. 257 ◽  
Author(s):  
R. Karthikeyan ◽  
V. Balasubramanian
Keyword(s):  
Sensitivity Analysis ◽  
Aluminum Alloy ◽  
Process Parameters ◽  
Spot Welding ◽  
Welding Process ◽  
Friction Stir Spot Welding ◽  
6061 Aluminum Alloy ◽  
Friction Stir

Simulative Model for the Evaluation of Thermo-Mechanical Effects in Friction Stir Spot Welding (FSSW) of Aluminum Sheets

2014 ◽  
Vol 622-623 ◽  
pp. 557-566
Author(s):  
G. D’Urso ◽  
Claudio Giardini
Keyword(s):  
Process Parameters ◽  
Spot Welding ◽  
Welding Process ◽  
Friction Stir Spot Welding ◽  
Lap Joints ◽  
Local Pressure ◽  
Friction Stir ◽  
Welding Forces ◽  
Set Up ◽  
Simulative Model

A study was performed to evaluate how the Friction Stir Spot Welding process parameters affect both the thermal distribution in the welding region and the welding forces. An experimental campaign was performed by means of a CNC machine tool and FSSW lap joints on AA6060-T6 aluminum alloy plates having a thickness of 2+2 mm were executed. Five thermocouples were inserted into the samples at a specific distance from the specimen center. A set of tests was carried out by varying the process parameters, namely rotational speed, axial feed rate, plunging depth and dwell time. Axial welding forces were also measured during the execution of the experiments by means of a piezoelectric load cell. The experimental data collected were used to set up and to validate a simulative model of the process. In particular, a 2D FEM model was set up using the commercial code Deform 2D. A 2-dimensional FEM code was preferred in order to guarantee a very simple and practical model able to achieve results in a very short time. Since it is not possible to simulate the rotation of the tool in a 2D configuration, a specific external routine for the calculation of the developed thermal energy due to the friction between tool and workpiece was set up and implemented into the code starting from the local pressure distribution along the contact area.

Electrically Assisted Friction Stir Spot Welding of Aluminum Alloy to Advanced High Strength Steel

2017 ◽  
Author(s):  
Kai Chen ◽  
Xun Liu ◽  
Jun Ni
Keyword(s):  
Aluminum Alloy ◽  
Material Flow ◽  
Spot Welding ◽  
Aluminum Matrix ◽  
Welding Process ◽  
Friction Stir Spot Welding ◽  
Steel Matrix ◽  
Friction Stir ◽  
Lap Shear ◽  
Electrically Assisted

This paper studies an electrically assisted friction stir spot welding (FSSW) process for joining aluminum alloy 6061-T6 to TRIP 780 steel. The electrical current shows to reduce the axial plunge force and assist the material flow of the aluminum matrix during the welding process. When electrical pulses and direct current (DC) with the same energy input are applied, the results show insignificant differences. Bulk material flow can be observed in the weld cross sections. A more uniform hook is generated at the Fe/Al interface after applying the current. Besides, the diffusion of aluminum atoms into the steel matrix is enhanced. Regarding the weld quality, electrically assisted FSSW improves the joint lap shear strength when compared with regular FSSW process.

Effects of Process Parameters on Friction Stir Spot Welding of Aluminum Alloy to Advanced High-Strength Steel

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Kai Chen ◽  
Xun Liu ◽  
Jun Ni
Keyword(s):  
Aluminum Alloy ◽  
Process Parameters ◽  
Cross Sections ◽  
Spot Welding ◽  
Dwell Time ◽  
Friction Stir Spot Welding ◽  
Thin Layers ◽  
Weld Strength ◽  
Friction Stir ◽  
Lap Shear

This paper studies a friction stir spot welding (FSSW) process that has been successfully applied to join aluminum alloy 6061-T6 to transformation-induced plasticity steel (TRIP) 780/800 steel. Cross sections of weld specimens show the formation of a hook with a swirling structure. A higher magnified scanning electron microscope (SEM) view of the swirling structure with energy dispersive X-ray spectroscopy (EDS) analysis reveals that it is composed of alternating thin layers of steel and Al–Fe intermetallic compounds (IMCs). To check the effect of different process parameters on the weld strength, the effects of tool plunge speed and dwell time were studied through the design of experiments (DOE) and analysis of variance (ANOVA) method. It shows that dwell time is a more dominant parameter in affecting the weld strength than plunge speed. Furthermore, investigation of failure using a lap shear tests reveals that cross nugget failure is the only failure mode. It also shows that cracks are initiated in the swirling structure at the tensile side of the weld nugget. After failure, a cleavage feature can be observed on the fractured surface.

Dissimilar Friction Stir Spot Welding without Key Hole between AZ31B Magnesium Alloy and 5052 Aluminum Alloy

2013 ◽  
Vol 652-654 ◽  
pp. 2320-2325 ◽  
Author(s):  
Xi Jing Wang ◽  
Ting Kai Guo ◽  
Zhong Ke Zhang ◽  
Pei Chung Wang ◽  
Ji Peng Shi ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Magnesium Alloy ◽  
Spot Welding ◽  
Welding Process ◽  
Friction Stir Spot Welding ◽  
Tensile Fracture ◽  
Az31b Magnesium Alloy ◽  
Friction Stir ◽  
Welding Joint ◽  
The Impact

To study the impact of the welding process parameters on the spot weld surface molding, mechanical performance and the stir zone microstructure, we use friction stir spot welding without keyhole method which designed and developed by ourselves to carry on the lap welding between 1mm sheet of AZ31B magnesium alloy and 3mm sheet of 5052 aluminum alloy with magnesium on top and aluminum bottom. The result of the orthogonal test shows that the shoulder friction time have a greater impact on the forming of the surface of the welding joint; When the rotating speed of 1000 r/min, shoulder friction time of 4s, pin length of 3.5mm, the tensile shearing force of the welded joint achieves its maximum value of 2.46 KN.Through observating the microstructure of the welding joint’s section stirring zone, we found the typical joint microstructure of Dissimilar metal. Through analyzing the microstructure of the tensile fracture, we found that fracture was cleavage fracture.We also found the fracture mechanism of the welding joint was cleavage fracture in microcosm but brittle fracture macrocosm.

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